This invention relates to a novel high protein, low fat foodstuff material which is comprised of a uniquely prepared protein curd product, and the process for the preparation of this material.
The rapidly increasing cost of food products and the world-wide shortage of food products has resulted in extensive research and marketing of food supplements and replacements. Soy bean products have been used extensively in this regard based on their availability, relatively low cost, protein content and compatability with other food materials. The prior art is replate with textbooks, patents and papers which have been made available regarding this subject matter. A meaningful summary of the state of the art is provided in Vegetable Protein Processing by L. P. Hanson (Food Technology Review No. 16, Noyes Data Corporation, 1974) and Soybeans: Chemistry and Technology Vol. I Proteins by A. K. Smith and S. J. Circle (AVI Publishing Company, 1978). A typical prior art process for preparing protein foodstuff materials from soy bean protein, casein, wheat gluten and the like is described in U.S. Pat. No. 3,674,500 to Nagasawa et al (July 4, 1972).
Most of the prior art processes have a common objective of providing an acceptable food substitute or supplement which has the desired properties of good texture and mouth feel, light color and bland taste. However, the complexities associated with the extensive, elaborate and numerous processing steps which are required to obtain products having the desired set of properties significantly increase the cost of the final product.
In many instances, the process involves precipitating protein from a water extract at the isoelectric point (pH between 4.0 and 5.0) and thereafter washing and drying the isolate (precipitated protein). The isolate is neutralized by alkali and redissolved in water for coagulation. Sometimes heat denaturing is used for coagulation and in some instances, protein solution is spun into fiber in a coagulation bath. Repeated washings with water are frequently required after coagulation. Needless to say, such numerous process steps are time consuming and add to the cost of the product. Attempts have been made to reduce the processing costs by utilizing extruded texturized vegetable protein having fibrous or spongy type structures.
Many of the products produced by prior art processes have a coarse and tough texture and/or a dry, grainy and pulpy mouth feel. Others have an undesirable flavor which is difficult to remove or an undesirable coloring which limits their applications. While they generally are employed primarily as a food supplement such as a filler or extender, they have limited use as a food substitute or a food item for direct consumption.